This invention relates to keyless entry systems. More particularly, this invention relates to a keyless entry system having a passive signaling device and a controller that operates in more than one mode depending on the presence of the passive signaling device.
There are a variety of keyless entry systems currently available. One use for such systems is for gaining access to a vehicle. The systems also sometimes provide the ability to remotely control various features of the vehicle such as an ignition switch.
There are problems with the currently available keyless entry systems. One example is the possibility for the signal from a remote signaling device (i.e., a keyfob) to be intercepted and later copied by an unauthorized individual such as a car thief. One attempt at avoiding such signal interception has been to encrypt the signals from the remote transmitter.
Another keyless entry system feature is a keypad mounted on an exterior panel of the vehicle, such as a door. A difficulty associated with such keypads is that encryption is not possible because an individual must manually enter the code each time access to the vehicle is required. Another difficulty associated with such keypads is they frequently have toggled buttons such that each side of the switch is used for a different portion of the entry code. These toggled switch arrangements provide a more aesthetic keypad because it is smaller, however, there is an increased risk that the wrong number will be entered by the user.
Another feature of some keyless entry systems is a passive device such as a card or a key head that provides a signal to the system without requiring any button or switch activation by the user. One drawback associated with such passive devices is that they must be held in very close proximity to the vehicle. This often results in annoying the user who has to hold the device very close to the vehicle before the device operates properly. Passive devices that provide stronger signals and do not require such close proximity are not without drawbacks. Stronger signaling passive devices can result in inadvertent activation of the system by casually passing by the vehicle even when the user does not wish to activate the keyless entry system.
Another difficulty associated with the remote signaling devices is the possibility for an individual to leave the device in the vehicle by accident. This presents a difficulty in allowing the user to gain access to the vehicle if the remote signaling device is locked within the vehicle. Another difficulty with such situations is when the vehicle is left unlocked, and an unauthorized user may gain access to the remote signaling device and, consequently, have full access to the vehicle.
There is a need for a keyless entry system that balances the considerations of providing relatively easy access to the vehicle for an authorized user while simultaneously providing enough safeguards to make the system secure and effective. This invention balances those needs in a manner superior to previously proposed keyless entry systems.
In general terms, this invention is a keyless entry system that operates in one of two modes depending on the presence of a passive signaling device. The system includes a passive signaling device that automatically provides an authentication signal. At least one other signaling device provides an access signal upon some manual activation by a user. A controller determines whether an authentication signal has been received from the passive signaling device. When a proper authentication signal is received, the other signaling device can be operated in one of two possible modes of operation. If no authentication signal is received from the passive signaling device, only one mode of operation of the other signaling device is acceptable before the controller will allow access to the vehicle.
In one example, the other access device is a keypad on the vehicle. When the passive signaling device provides a proper authentication signal, pressing any number on the numeric keypad results in the controller permitting access to the vehicle. If the passive signaling device is not present, however, a specific code must be entered using multiple keys on the numeric keypad before the controller will allow the desired access to the vehicle.
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows.